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Posted to commits@trafodion.apache.org by db...@apache.org on 2018/01/18 18:47:10 UTC
[2/5] trafodion git commit: Add Considerations for ROLLUP
Add Considerations for ROLLUP
Project: http://git-wip-us.apache.org/repos/asf/trafodion/repo
Commit: http://git-wip-us.apache.org/repos/asf/trafodion/commit/ab26bec4
Tree: http://git-wip-us.apache.org/repos/asf/trafodion/tree/ab26bec4
Diff: http://git-wip-us.apache.org/repos/asf/trafodion/diff/ab26bec4
Branch: refs/heads/master
Commit: ab26bec4d6a41c6f9217c6719f6736e4c3d4701f
Parents: 233d096
Author: liu.yu <yu...@esgyn.cn>
Authored: Tue Jan 16 15:58:38 2018 +0800
Committer: liu.yu <yu...@esgyn.cn>
Committed: Tue Jan 16 15:58:38 2018 +0800
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.../sql_functions_and_expressions.adoc | 25 ++++++++++++++++++++
1 file changed, 25 insertions(+)
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http://git-wip-us.apache.org/repos/asf/trafodion/blob/ab26bec4/docs/sql_reference/src/asciidoc/_chapters/sql_functions_and_expressions.adoc
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diff --git a/docs/sql_reference/src/asciidoc/_chapters/sql_functions_and_expressions.adoc b/docs/sql_reference/src/asciidoc/_chapters/sql_functions_and_expressions.adoc
index 8f5ab1b..764c749 100644
--- a/docs/sql_reference/src/asciidoc/_chapters/sql_functions_and_expressions.adoc
+++ b/docs/sql_reference/src/asciidoc/_chapters/sql_functions_and_expressions.adoc
@@ -6358,6 +6358,31 @@ For example, a query that contains three rollup columns returns the following ro
NOTE: Trafodion does not support CUBE function which works slightly differently from ROLLUP.
+[[considerations_for_rollup]]
+=== Considerations for ROLLUP
+
+[[null_in_result_sets]]
+==== NULL in Result Sets
+
+* The NULLs in each super-aggregate row represent subtotals and grand total.
+* The NULLs in selected columns are considered equal and sorted into one NULL group in result sets.
+
+[[using_rollup_with_the_column_order_reversed]]
+==== Using ROLLUP with the Column Order Reversed
+
+ROLLUP removes the right-most column at each step, therefore the result sets vary with the column order specified in the comma-separated list.
+
+[cols="50%,50%"]
+|===
+| If the column order is _country_, _state_, _city_ and _name_, ROLLUP returns following groupings.
+| If the column order is _name_, _city_, _state_ and _country_, ROLLUP returns following groupings.
+| _country_, _state_, _city_ and _name_ | _name_, _city_, _state_ and _country_
+| _country_, _state_ and _city_ | _name_, _city_ and _state_
+| _country_ and _state_ | _name_ and _city_
+| _country_ | _name_
+| grand total | grand total
+|===
+
<<<
[[round_function]]
== ROUND Function